Due to the quick progress and development in the information technological field, the currently available electronic products all are designed to have high performance, high frequency, high operating speed, and minimized weight, thickness and volume. On the other hand, these electronic products also generate more and more heat during operation thereof. Since the high amount of heat produced during operation would adversely affect the reliability and the service life of the electronic products, it has become an important issue as how to remove the produced heat from the electronic products.
Presently, cooling fans are widely employed as a device to remove the operation-produced heat from the electronic products. Almost every electronic product is internally provided with a fan for keeping the electronic product within a preset working temperature range. However, it is possible one single fan does not provide sufficient air flow to ensure good heat dissipation effect of the electronic product. To enable enhanced heat dissipation, a plurality of fans may be serially connected to form a serial fan for drawing in increased air volume and producing increased air flows. In using the serial fan, a user might increase the fan's rotating speed to obtain upgraded heat dissipation efficiency. The serial fan operating at the increased rotating speed will vibrate and produce noise due to a resonant effect between the serially connected fan frames. This condition will cause reduced stability of the electronic product.
FIG. 1 shows a prior art serial fan, which includes a first fan 10 and a second fan 11 serially axially connected to each other. When the first and the second fan 10, 11 are caused to rotate at an increased speed in order to meet the requirement for heat dissipation, the two fans 10, 11 will vibrate and produce noise due to a resonant effect between the two fans 10, 11. To overcome this undesirable condition, a vibration-absorbing member 12 is disposed between the two fans 10, 11 for absorbing the vibration produced by the first and the second fan 10, 11 during operation thereof. The additional vibration-absorbing member 12 would increase the assembling cost of the serial fan and tends to cause defects of the serial fan when being poorly assembled to the two fans 10, 11.
In brief, the prior art serial fan with additional vibration-absorbing member has the following disadvantages: (1) requiring increased assembling cost; and (2) tending to have defects due to poorly assembled vibration-absorbing member.
It is therefore tried by the inventor to develop an improved anti-vibration serial fan to overcome the drawbacks in the prior art serial fan.